A contract agreement struck Thursday by the Metropolitan Transportation Authority and its largest union fell short of the agency's stated goal of no net increases in labor costs, but officials said the pact won't result in fare increases or alter plans for service or capital projects.

The agreement—which the Transport Workers Union Local 100 board voted 33-0 to approve Thursday night—could set the stage for other transit and municipal unions in their own looming negotiations. The full membership of about 34,000 employees...